GAF 3.5 in. 4 ft x 8 ft EnergyGuard Grade-II (20 psi) Polyiso Roof Insulation Panel

This GAF EnergyGuard Grade-II (20 psi) polyiso insulation panel measures 4 ft x 8 ft and is 3.5 in. thick, with glass fiber reinforced cellulosic felt facers over a polyisocyanurate foam core. One panel covers 32 sq ft; a 13-piece bundle covers 416 sq ft. It installs in low-slope roof systems and pairs with GAF single-ply, mod-bit and BUR membranes.

Key Features:

• High thermal value: Polyisocyanurate foam core delivers high thermal efficiency for low-slope commercial roofs.
• 20 psi Grade II: Classified ASTM C1289 Type II, Class 1 Grade 2 (20 psi) compressive strength.
• Large 4x8 format: The 4 ft x 8 ft panel covers 32 sq ft for faster installation on open roof fields.
• Broad system approval: System approved for modified bitumen, BUR and single-ply assemblies.
• Third-party listings: FM Approved 4450/4470, UL 1256/790/263, UL ER1306-03, Miami-Dade County and State of Florida approved.
• Sustainable content: Green Circle Certified for recycled content and contributes to green building rating systems.
• Field friendly: Lightweight and easy to cut for efficient handling and installation.

Specifications Table:

Coverage & How Much You Need:

One 4 ft x 8 ft panel covers 32 sq ft; a 13-piece bundle covers 416 sq ft. Divide total roof area by 32 sq ft per panel to estimate quantity and follow the tapered layout plan for slope and drainage design.

Fit and Compatibility:

Compatible with GAF EnergyGuard tapered insulation systems and TPO and PVC membranes in adhered, mechanically attached and induction welded systems, plus mod-bit and BUR assemblies. Membranes, adhesives, plates and fasteners sold separately.

Frequently Asked Questions (FAQ):

Q: What comes in one sell unit?
A: Each selling unit is one 4 ft x 8 ft, 3.5 in. thick panel; panels ship 13 to a bundle covering 416 sq ft.

Q: How do I calculate how many panels I need?
A: Divide the roof area in square feet by 32 (one panel's coverage); one 13-piece bundle covers 416 sq ft.

Q: Is this panel tapered?
A: It belongs to the GAF EnergyGuard tapered polyiso line, which is offered in slopes from 1/16 in. to 1/2 in. per foot; the specific slope of this item is not stated in its spec lines.

Q: What is its compressive strength?
A: It is ASTM C1289 Type II, Class 1 Grade 2, rated at 20 psi minimum compressive strength.

Q: Which membrane systems can it be used with?
A: It is approved for modified bitumen, BUR and single-ply systems, including TPO and PVC installed adhered, mechanically attached or induction welded.

Q: How should it be fastened?
A: Install per the GAF data sheet and tapered design; panels can be mechanically attached with fasteners and plates or set in low-rise foam per system requirements.

Expert Verdict — Reviewed by the SuperArbor Pro Desk

For big open roof fields, 4 ft x 8 ft panels reduce joint count and install time versus 4 ft x 4 ft stock. Verify the specified slope designation against your tapered layout before ordering, since this line ships in many slope/size combinations. Keep bundles wrapped and dry until install, stagger joints, and use a GAF-approved cover board where a Class A assembly over combustible decks requires one.

Follow the manufacturer's installation instructions and local code, and use proper fall protection and lifting technique when handling large insulation panels on the roof.

Order GAF EnergyGuard Grade-II 20 psi polyiso insulation 4 ft x 8 ft panels for faster low-slope coverage.